Topic: Is quartz a silica atom bound to three or four oxygen atoms: (Read 395 times)

I was reading about quartz and how it is a crystalline structure based off a tetrahedron (silicon in the center and 4 oxygen molecules around it). However, all the images (including those from Wikipedia and UNSW Sydney) show quartz as a silica atom attached to only three oxygen atoms. This type of image is also rampant when I do a google search, so I have to ask: "is quartz (and glass) a silica atom bound to three or four oxygen atoms"? If it is bound to four, why are they only showing three bonds in the images?

These are poorly drawn, flat 2D representations of a 3D structure, kind of a flattened cross section. As you wrote, Si atom sits in the center of a tetrahedron with four oxygen atoms (not molecules!) occupying all four vertices.

Sadly, it is quite difficult to represent this structure in a clear, unambiguous way on a paper.